Sleep apnea is a serious disorder characterized by complete cessations of respiration during sleep. Current work indicated that 35% of VA inpatients >60 years old have more that 5 apneas per hour of sleep and 13% have over 20 apneas per hour of sleep. Little is known about the natural history, clinical implications, or risks of such wide-spread apnea. The first goal of this study is to describe the natural history and progression of sleep apnea and periodic leg movements in sleep (PLMS, a disorder of leg kicks during the night). Seventy-five elderly VA patients, already recorded between 1987-1989, and 37 independently-living elderly who have been previously recorded, will be rerecorded every two years for a four-year period. Each person will be recorded with a modified Medilog/Respitrace portable recorder and with oximetry for two nights. In addition, sleep symptoms and medical history will be followed. Clinically, we need to know how commonly a patient who was found to have significant sleep apnea continues to have apnea and related morbidity. The second goal is to examine the relationships between sleep apnea and mortality by following 700 elderly subjects who have been prospectively recorded in three studies. These subjects' survival will be followed to see if apnea predicts increased mortality.